I mailed my taxes how do i know they got it

[mesquitebean]

Who are "they"?   The IRS?
Are you due a Federal refund, or did you have to pay taxes due?

[brieemarie]

Yes the IRS. I am due a federal refund

[mesquitebean]

If you mailed the return, unless you used a method that has tracking such as Priority Mail or certified return receipt, you won't know for some time if they received it.

Since you are due a Federal refund, at approximately 4 weeks after mailing, you see it show up in this IRS tool "Where's My Refund":

https://www.irs.gov/refunds

It takes about 6 weeks from mailing to get a Federal refund for a paper return.