For now, I am going to assume that you are a somewhat weaker player.
If that is the case, virtually 90% of your time should be spent on tactics for now, but you want to find them grouped by category, so you are constantly solving similar problems. Try to do 50 per day, spending no more than two minutes per problem.
In addition to that, you want to find a good endgame course, like "Silman's Complete Endgame Course". At times, when you want a break from the tactics, start reading through that book page by page. Frankly, do not try to deeply study it at first. You should prefer to just see many, many, examples played out, and try to absorb as much as you can by osmosis, rather than deeply studying at first. There are a few things that need to be memorized, like how to draw K+P vs. K when your lone king is in front of the pawn, or the Lucena position to win certain rook endgames, or Philidor's position to draw certain rook endgames.
Lastly, you can also spend some time with opening pawn structure books, like Soltis' "Pawn Structure Chess". There are analysis mistakes in it galore, but the overall ideas are sound, and will teach you HOW to play chess rather than trying to memorize opening theory.
Spend most of your time on the tactics, but take breaks, and dabble in the other two. As you get stronger, things will change.
You can also read my answer here for more advice.
