This article explains how to add an email address to your Gmail contacts, and then edit the contact to add more information, such as their name. Instructions apply to Gmail on the desktop via a browser.
Besides making a new contact’s information available on other devices, another reason to add a contact to Gmail is so that they’re recognized by Google and not sent to spam. Here’s how to add an email address to your Gmail contacts.
Open a message from the sender you want to save as a contact in Gmail.
Hover the cursor over the sender's name at the top of the email.