Other people won't be able to see how much you donated, per donation or in total. If your profile is set to private, only followers you approve will be able to see which nonprofits you supported. If your profile is set to public, anyone on the web will be able to see which nonprofits you supported. Youcan always change your privacy setting in Edit Profile.
If you would like to hide a specific donation, you can go to your profile and click on the kebab menu and click "Hide this donation" which will remove it from all feeds.