I added funds and invested in a pie on my desktop computer last night but this morning I checked the app and it asks me to add funds like havenāt yet.
Itās almost like the same account is working differently/separately on different devices.
Iām not trying to use two accounts, itās exactly the same one, just like the app hasnāt updated itself with the information contained on the account - even though itās signed in.
Any ideas?
Welcome to the Community, @torqueing 
Itās very likely that you have opened two accounts, for example, an Invest and an ISA, and youāve funded only one of the two accounts.
You can easily switch between accounts on the mobile app by going to settings and selecting the correct account from the menu at the top. When using the web app, just click on your account balance in the top left corner and select your desired account from the pop-up screen 
Ah yes. It appears to be in a stocks ISA for some reason. Is there any reason to change it? Can I add/remove it just like I was investing?
If you withdraw funds from the Pie, you can freely transfer them to another account by going to āManage fundsā. Thereās an older thread in our Community here that covers the difference between the ISA and Invest accounts.
@torqueing Be aware, investing in the ISA account over the Invest account means you dont pay tax. Any capital gains or income (dividends) earned from investments within an ISA are tax-free.
Youāre always better off using up your 20k per yr ISA allowance before investing in a GIA (General Investing Account, in this case the Invest account).
Thanks for the quick replies. Iām thinking of getting the Trading212 card, for that to work would the cash and stocks need to be in the trading account instead of the ISA then?
Also, Iām looking to withdraw some of the money. Nowhere either in the card section (which is linked to my bank account) or in settings can I see how to withdraw funds.