You can provide SMTP server you want to use for sending emails by login to your Admin account. Just go to Settings page and click on SMTP tab. You will see form shown in the following screenshot. The example for adding Gmail SMTP server is shown in it. You can change the values according to your requirements. If you decide to use Gmail as your SMTP server then you have to turn on two factor authentication on your Gmail account as shown here and generate App password to use it for SMTP. You can generate App password as shown here. You can use your email as the SMTP Username and App password you generated as your SMTP Password.
Note :- If your SMTP doesn't work for some reason then you can set Debug to Server. It will record more detailed information about the error it encountered while connecting to SMTP server. Now just try to create new user or do anything else that trigger the sending of an email. If it fails then you will be able to see the debug information from the SMTP tab of settings page. You will see "Show debug information" link besides Debug. You can click on it to see the SMTP debug information.
