How to create a page where people can fill things out electronically

want to have my clients be able to fill out information I ask them through a website or document that they can fill out straight from their phones and send back or save and I get the information, what would be the best way to do this? Like filling out paperwork electronically ? Is there a certain webpage I should use or software? I’m honestly in the medical friend and don’t know where to begin, last time I did something like this I was editing my myspace profile lol ..

Thanks for all your help in advance you reddit geniuses