1. Open Gmail in your web browser
2. Click the gear icon at the top-right of the page
3. Click See all settings:
4. Click on the Accounts tab:
5. Go to the Send mail as section and click Add another email address:
6. Enter the name you want to recipients to see (e.g. Your Company Name)
7. Enter the email address you want to send mail as (e.g. info@yourcompanyname.com)
8. Make sure Treat as an alias is checked, then click Next Step:
9. You will be prompted to send a verification email to confirm you have access to the new address; click Send Verification:
10. Once you receive the verification email, you can simply click the link to confirm access, or you can copy/paste the code into the Gmail prompt -- either way is fine.
Now when you compose a new email you should see a dropdown arrow in the From section; simply click the dropdown and choose which address you'd like to send as: