Studies have proven that the actual numbers of "illegal" votes are SO few as to be a complete non factor, refuting Trump's claims of "millions" of them;
https://www.bbc.com/news/articles/c5yj98grr5lo
From the quoted article;
" It found that out of 23.5 million votes counted in these states, an estimated 30 suspected incidents of non-citizens voting were referred for further investigation.
That’s about 0.0001% of all votes cast."