the default is a check unless you provided your banking account information to the IRS (or social security)

I've been hearing that turbo tax is having paper checks sent to temporary bank account instead of it being mailed to me like I wanted 

not true.  Turbo Tax has nothing to do with this.

The IRS will direct deposit to whatever they have on file for you.  if that account is closed, then it will send out a paper check.

you can update your financial information here: 

 Check the IRS website and update your bank information if necessary.

  AGI is line 7 on your 2018 return and line 8B on your 2019 return.  Refund is line 21a of the 2019 tax return. and line 20a for 2018

https://www.irs.gov/coronavirus/economic-impact-payments