Give each user their own user account on the computer. Firefox will create a profile for each user.

HI If you want to use just for one user you have make another profile. Make another profile just for one user. To make another profile follow this links, How To make Firefox Profile. Another one

Read through any one link hope it will help you

See these articles to learn how to create separate Windows 10 User Accounts. http://www.windowscentral.com/manage-user-accounts-windows-10

http://www.howtogeek.com/226540/how-to-create-a-new-local-user-account-in-windows-10/

http://www.howtogeek.com/224847/how-to-set-up-and-configure-user-accounts-on-windows-10/

That is very important because in addition to Firefox being shared when using one Windows User Account, all your data files for every program you use is exposed to anyone who might poke around your drive. There is no privacy for anyone who is using a shared Windows User Account!