Turbotax users

If you purchased the TurboTax software, it can only be installed on up to 5 computers that you own.  The software can be used to e-file up to 5 tax returns.  All other tax returns over the 5 e-file limit would have to be printed, signed, dated and mailed.

You can complete and file a tax return for anyone provided you do not require payment for the tax return.

The license says you can install the program on up to 5 computers that you own, which you can then use to prepare returns friends and family, as long as you don't charge for your services (which is a violation of the license and IRS regulations).   The license does not say you can share the download with 4 other friends, although some people think that is what it means. 

Either way, your license activation code is linked to your online account and you get a maximum of 5 activations.

Separately, the IRS limits each personal filer to 5 e-filed returns.   This limit is enforceable by the IRS per user even if you buy a second copy of the program to get 5 extra activations.  We don't know exactly how that is enforced, so we can't tell you if you can get around that limit by installing the program on different computers.  If you need to file more than 5 returns, expect to print and mail them.  

To hold down on fraudulent returns the iRS wants those e-filing more than 5 returns to register 

https://www.irs.gov/e-file-providers/become-an-authorized-e-file-provider 

this would also require you using one of Intuits professional tax return apps since form 8879 for 1040 (other versions for corpurations, trusts and partnerships) is required

don't know what penalties the IrS can impose,if any, on those violating the 5 return limit