I have edited and saved it in General settings, but it doesn't seem to reflect the change in the POS.

I guess you want to change the text, which appears on the receipts. You have to check "Header" and "Footer" fields in the "Receipt" chapter in Settings in the Back Office. 

 

Hello, 

In the  POS menu  is shown the name of the store and not the "Business name" that you see in General settings in your Back-office.

                                                                               

So you need to change the name of the store if you want to change the name that appears in the POS menu.

You can change the name of your store from the Back-office-> Settings-> Stores-> click on  the store->Edit the name of the store and press SAVE.