I just searched several sites where masks are being requested/accepted. These instructions, from Allina in Minnesota are typical of those offered: https://www.allinahealth.org/-/media/allina-health/files/mask-sewing-how-to.pdf Please note that the masks need to be 100% cotton, with elastic or with 100% cotton bias ties, in order to be of use to them.
They are not the same as many tutorials being offered on Facebook, YouTube, etc. If you are going to the effort of making masks, please be sure they can be safely used.
Even if the providers themselves, in any setting, can tolerate latex (as in rubber band ear loops) they have no way to know whether their patients can. That is why nearly all health care providers have transitioned away from latex of any kind. In most hospitals they do not even permit latex balloons due to risk of serious reaction.