If in a tournament game, white is only aiming for a draw, what openings and strategies will be recommended for him? I guess that the answer may depend on the following different mindset for black:
I am aware of a related question but my questions seems to be different.
The English Opening (1.c4) is excellent for pushing for a drawish line. There's not many risky/sharp lines in it.
The Reti Opening (1.Nf3) is also a good "safe" opening without too many sharp lines.
In both of these, flexibility is key.
These delay committing to either "wing pressure" with minor pieces or "center occupation" with pawns; white can adapt to whatever black throws out and slow things down, whether black wants to win or is looking for a draw themselves.
If black is looking for a win, the French Opening might be a possibility - most lines are fairly defensive (not all - some are very sharp and should be avoided by white) and can push said player into being so aggressive as to make a mistake that could even hand white an easy win.
Note: (suggested by @ATLPoly)
With both the Reti and the English, it is possible to play sharply with moves like f5. These aren't the best lines for black, but be warned that they are sharp and do require white (and black to a greater extent) to play accurately, even though the position is slightly in white's favor.
The best way to play for a draw as White is to stick to your main opening repertoire, only avoiding the sharpest lines where you are not sure of the latest analysis.
Playing an opening you know well prevents you from misshaps in the first phase of the game and arms you for the early middlegame. Moreover, if your repertoire is decent, it generally leads to equal or better positions for White, from where it will be easier for you to lead the game into dull waters (e.g. positions with symetrical pawn structures, mass exchanges, or forced lines leading to perpetual check).
A tactical line is not necessarily to be avoided. A common psychological trap is to avoid calculating any variation by fear of a calculation error, play passive moves, and drift surely and not-so-slowly into a lost position. If you stop yourself from using your capabilities (tactics, calculations), you diminish your own playing strength. Compared to a "normal" game, however, you can evaluate differently the positions reached in your calculations: even if you are slightly better, a perpetual is fine, a drawn endgame also.
Let's assume you are a 1.e4 player, for instance. If you go 1. c4 or 1.Nf3, you probably won't face any disaster in the opening, however after move 10 you will find yourself in unknown territory, in an equalish-but-with-a-lot-of-play-left position and with a lot of decisions ahead to make by yourself. Moreover, exchanges don't come for free in positional lines, if you aim for them you will often trade your good pieces and keep the worst ones.
On the other end, if you play your usual 1.e4, you can use your knowledge to navigate through the opening without huge mistakes and it is your opponent's job to make something special happen and create chances for himself.
He will probably refrain from the French for fear of the exchange varaition, or from 1...e5 because White can aim for liveless positions in, say, the 4 knights or the exchange Ruy Lopez. In case of a Caro-Kann, your usual line is probably not very risky for White, but you can also go for a Panov: isolani positions can get very sharp when White plays for an attack, but Black cannot do much to avoid simplifications if you simply play for d4-d5 and exchanges.
Against rarer stuff like Pirc, Scandinavian or Alekhine, your usual repertoire probably yield a small plus for White. If you go for it, you will be in a good position to force simplifications later in the game.
The tougher nut to crack, or rather to tame, of course, would be the fiery Sicilian. There you have a choice: if you are confident in your theoretical knowledge, you can prepare your opponent's usual main variation having in mind that all the equal-and-simple lines and all the perpetuals are okay for you. That makes White's preparation much easier actually. Or you could go for something solid like the c3-sicilian, where (as in the Panov) some games can get wild but that is merely when White goes for an attack. If you play in the center and look for simplifications, you will very often get them.
TL;DR
Don't change your very first moves, but adapt your play to your goal only when you start calculating lines at the end of the opening and in the early middlegame. Don't forget that it is much easier to force a draw from a slightly better position than from a slighty worse one.
The main ideas in playing for a draw are to exchange as many pieces as possible, and to avoid getting into a sharp opening. This simplifies the position and reduces the tendency of either side to blunder. For each case, some openings are suitable.
If black is OK with a draw, then 1. e4 is the best. The only risk of drawing the game here is getting a sharp opening in return (a Sicilian, for example), which your opponent won't do if they are playing for a draw.
If your opponent is playing for a win, then open with 1. d4. A typical reply is a QGD, or perhaps a Slav defense. In both cases, to draw you would go for an exchange variation:
[FEN ""]
1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. cxd5
[FEN ""]
1. d4 d5 2. c4 c6 3. cxd5
It is a long-held opinion of the Soviets (now Russians) that when you play for a draw, you are really playing for a loss.
You should play normal chess, and trade down when it simplifies the position without degrading it. Of course, the more you simplify, the more you need to understand about the endgame.
Playing for a Draw is against the Laws of Chess (1.4: The objective of each player is to place the opponent’s king ‘under attack’ in such a way that the opponent has no legal move.) And it is the simplest way to lose.
If you need a draw, play good chess. The best chess you can play. If you are good in endgames, simplify. If you are good in tactics, make it complicated. Play the opening you have played for decades because most probably you know its positions better than your opponent. And avoid doing anything special for draw’s sake that you would not do if playing for a win or for fun.
