I amended my return in July and they said it would be mailed and I haven’t received it yet, how do I know if it was mailed?

The status of the amended federal tax return will be on this IRS website - https://www.irs.gov/filing/wheres-my-amended-return

Any tax refund on an amended return will only be mailed as a check to the address on the amended tax return.

Or if you are referring to the actual mailing of the amended return, only you can print, sign, date and mail the return to the IRS.