When e-filing, does one need to explicitly attach Form 8938 (if filled) before submitting? Unlike paper filing, e-filing with most softwares only seems to print Form 1040 and Schedule B. Are other forms and schedules we filled also submitted to IRS by these softwares during e-filing, even though they are not printed as part of the return ?

Not sure about other tax software, but TaxAct has Form 8938 as an intergarl part of the return which DOES print out on the final return.