What file types should I permit for Resume uploading on forms ?

I am building a form using Formidable forms and just for like for word formats there is a zillion format extensions for WORD alone
, so my question is, what file format to we let people upload resumes in and what file sizes should be allow for a range ? Meaning up to 1 MB ? Or is that too much ?
I just need the list if doc formats because it is dizzying how many formats there are and what formats are usually used for Resumes ?
Also any other format people use these days to upload their resumes ?
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