Microsoft Outlook stores its emails and other items in something called Outlook Data Files (PST). These files store user contacts, emails, calendar events, and journals along with other data based items. These PST files are only accessible through Outlook configurations to which the data is saved on. Luckily, you can transfer those files to an alternate system or portable device like an external hard disk.
Type a password in both the Password and Verify Password text boxes and select [OK] again.
For example, this will be necessary when you open Outlook or when you decide to open the data file located in Outlook.
Further information can be found on the Microsoft website here: https://support.microsoft.com/en-us/office/create-an-outlook-data-file-pst-to-save-your-information-17a13ca2-df52-48e8-b933-4c84c2aabe7c#:~:text=On%20the%20File%20menu%2C%20point,file%2C%20and%20then%20choose%20OK