@Lily123: Are you using the Samsung Email app? If so, please open the app > Tap the 3 lines in the top left > Tap the cog in the top right of the pop up window > Manage Folders, and you can choose to show or hide the available folders for your registered email account. Let me know if this helps.
@Lily123: I'm glad to hear that you've found the folder you were looking for. Regarding the missing emails, try opening the Email app > Tap the 3 lines in the top left > Tap the cog in the top right of the pop up window > Select your account > Sync account > On > Sync period (or 'Period to sync emails') > Select 'All time'.
If you're still unable to access your saved emails, try signing in to your account via a browser app (Samsung Internet or Chrome) and check to see if the emails are visible in the saved folder here.