They will measure your arms span, height, how stretchy your skin is, ask you LOTS of questions about your medical history and childhood and before your appointment they'll test you for heart defects and eye defects too probably. They will also be checking you all over to look for stuff like peizogenic papules, atrophic or generally abnormal scarring but especially atrophic, and stretch marks especially if they're atypical like not usually where you get them or super big or deep, or if you wouldn't have a reason to have them normally. If they see certain they also make you do hypermobile things for the beighton test and to test for arachnodactyly. It's a lot, and if they see certain things that point to certain types of EDS they'll order genetic testing with your consent