Are you having a problem? Are you stuck somewhere?
How to Efile,
https://ttlc.intuit.com/community/e-file/help/how-do-i-e-file-my-personal-individual-tax-return/00/25891
You can either Efile your return to the IRS or print and mail it. If you efile it will get there faster. When you efile there is nothing you need to mail in.