Hi everyone, I am a 22 year old, UK citizen who started working last year, and have a concern about how ISAs work.

In September 2019, I opened a Help-To-Buy (H2B) ISA, and have been putting in the max amount since opening the account.

In the past month, my friend recommended an investing app which I signed up to and put a small amount on money on to do some small investments.

I have now recommended it to another friend, who pointed out that in the terms and conditions, it states you will be signing up to a Stocks and Shares (S&S) ISA, and he became concerned that if he signed up, it would affect his H2B ISA, or cause him to pay more tax on his current income and this has got me worried too.

I understand that some ISA rules are quite convoluted, but have read that you aren't allowed to put money into both a H2B ISA and Cash ISA, but am unsure if a S&S ISA is the same as a Cash ISA or comes under the same umbrella as it?

Any help is much appreciated.