If you do a quick search on the forms for "mobile hotspot" or quick toggle" you will find what you are looking for as this has been posted multiple times. The steps are also on XDA Developers.
yes there is a way but you do so at your own risk... https://www.xda-developers.com/how-to-restore-mobile-data-quick-settings-tile-toggle-on-samsung-galaxy-devices/
you can find detailed instructions here http://pconline.ca/downloads/restore_toggles.pdf it's based on the xda article and also includes directions to an automated script which works on the s7
