I had to mail my return from last year, how will II know when it has been filed

[Carl]

It was filed the day you mailed it. Generally it can take the IRS 6 weeks or longer to actually process it, once they receive it - assuming you mailed it to the correct address and they actually received it.

If you don't have an account already, you can create an account on the irs.gov website and check that way to see if it's been processed yet.

[Critter]

To track your Federal refund:   

https://www.irs.gov/refunds

To track your state refund:    

https://ttlc.intuit.com/questions/1899433