I used to use the official Bitcoin wallet which of course I knew how to use but I recently got suggested to use electrum because of it being much faster and easier to use. Can anyone tell me how I would go about importing my existing wallet.dat and private key into electrum?
You can import the plain text private addresses into Electrum just pasting it into a form one line after the other, example:
5Z45l3k-Private-address-1-xlkseLkel
55Z5l3k-Private-address-2-zlkseLk3s
54S5l3k-Private-address-3-zlkseLk3s
As stated above, easiest way is to send coins from Bitcoin Core to the new Electrum addresses. Reason being, you can restore your Electrum addresses from seed but that seed will not restore your imported addresses. I just use the import feature when importing paper wallets, that I then send to another address.