User Hauke Reddmann noted in a previous answer that there should be a straightforward way to secure selfmate against a substantially weaker opponent (i.e., force them to checkmate you):
win all the material of your opponent, except a safely blocked pawn. Then force your own mate by zugzwang. The minimum material needed is KQB/KP.
I queried a Problem Database for White to selfmate against Black with KQB vs KP, and found 17 such positions. All of these, however, seem to require Black's pawn to be a Knight pawn (on the b or g file). There may also be some other patterns that universally hold (does the White Bishop have to be the same color as the Black pawn's promotion square?).
My question is as follows: is it generally possible to force a selfmate with KQB vs KP (for example, we may take a randomly selected position like the below), or is it a requirement Black's pawn should be a Knight pawn? If it is generally possible to force the selfmate, what procedure should one follow to do so?
[Title "KQB vs KP, White to play & selfmate if possible"] [FEN "1Q1B4/8/6K1/3k4/3p4/8/8/8 w - - 0 1"]
Note: 'generally' means 'exceptional circumstances notwithstanding', such as for example if Black's pawn is so far advanced that it threatens promotion, or being so placed as to force White to capture it shortly, etc.