Whats the difference in using ''Trading 212 INVEST'' vs ''Trading 212 ISA''

You can have 2 ISAs but you cannot pay into more than 1 Stocks and Shares ISA in the same tax year. If you open an S&S ISA today and fund it you’ll be able to open a new one and fund it on April 6th. Investments made within an ISA are not subject to tax irrespective of your personal circumstances.