We do these all the time. Start to finish, it’s nearly always less than an hour’s work, counting back and forth between us for me to get the login & password information that is needed the first time. Renewals take a few minutes.
This certificate allows your site to be accessed via HTTPS (the “S” is for secure). It will make warnings by search entities like Google go away.
We also handle the changes that are needed to force your site to always be HTTPS.