best option to upgrade imac hard drive
hi all i have a 2015 iMac i bought refurbished from a local store here were i live, i think it has had some upgrades before as its showing it has 500GB ssd , but i would like options whats the best way to go about upgrading this to a 1tb , go with a external which i have but can't for the likes of me figure out how to install programs to it on mac os big sur. or take it to a shop and have them upgrade it?. any help appreciated god bless.
iMac 27″, macOS 11.2