Yes, each nomination source have their own requirements. You need to have a checklist for each MOC indicating dates needed, how many LORs required and from whom, and how to send it. For DS co2026 as example:
MOC#1 wanted paper LOR from any four sources in the community (no relatives) placed inside sealed envelopes but submitted altogether as part of a complete packet in one package.
MOC#2 was more high-tech, all three recommenders had to directly upload the file to the MOC website. DS provided the email addresses of any STEM teacher, one English teacher, one principal/counselor.
MOC#3 wanted all three recommenders to email their LOR to a specified email address, in a specified email Subject format containing the candidate-applicant name.
It is confusing, so stay organized and methodical to make sure you don't miss any requirements. If you're not very good at scheduling or just too bz with school, ask parents for help to track your checklists. Also, proactive followup with your recommenders especially if it's their first time doing it for an SA application. One tip is that you can re-use LORs but make sure they are addressed properly and sent in the format required. If a Math LOR is required by two MOCs, you can use the same Math teacher recommender just explain that the same letter can be submitted to two different recipients.
To help the recommenders give a deeper and more meaningful LOR, DS created a resume of his accomplishments in academics incl SAT/ACT/asvab/grades class-rank and awards, sports, leadership, community service. He also provided a one-page essay of why he wanted to apply to SA and how important it is to him, his aspirations (say next ten years) and dreams.
I believe the strong LORs helped DS gain appointments to USMA and USAFA. Ofcourse in addition to the whole person concept that's part of the SA application process.