Is it something I can do if I put two people on my return by mistake and want to take them off what will happen, and what can I do to make it right? Can it be fixed?

Did you claim someone you should not/could not claim?  If you already filed your return, then you have to wait for it to be fully processed and then you can amend it to remove those dependents.   Meanwhile those people cannot e-file their own returns if they are trying to file saying they cannot be claimed---which means they have to mail their tax returns and that they will not receive stimulus checks if they were otherwise eligible to receive them.

Who did you claim?  If they CAN be claimed then you do not have to change your return.

IRS interview to help determine who can be claimed:

https://www.irs.gov/help/ita/who-can-i-claim-as-a-dependent

IF you need to amend:

https://ttlc.intuit.com/questions/1908543-do-i-need-to-amend

How do I amend my 2019 TurboTax Online return?

A 1040X cannot be e-filed.  It must be printed and mailed.  It will take about 4 months for the IRS to process an amended return.  It is a good idea to use a mailing service that will track it, like UPS or certified mail, so you will know it was received.

Wait about 3 weeks from mailing and you can check the status of your amended return:

https://www.irs.gov/Filing/Individuals/Amended-Returns-(Form-1040-X)/Wheres-My-Amended-Return-1

https://www.irs.gov/filing/individuals/amended-returns-form-1040-x/amended-return-frequently-asked-questions

So that you know.....Amended returns are taking much longer than usual.  The IRS is not opening the mail now.  It will be longer than the normal 3 weeks to see anything on the Amended return site, and longer than 4 months for them to process the return.