Turned 70-1/2 last year and took my rmd this year before Apr 1. How do I show on my return, with no 1099-R?

[VolvoGirl]

You don't.  You enter it on your 2019 return next year.  Be sure to also take your 2019 RMD by Dec 31.  So you will have 2 RMD.

[Hal_Al]

Since you waited til 2019 to do a withdrawal, your 2018 RMD will be taxable in 2019. You do not have the option of declaring it taxable in 2018.
There is no where on the tax forms that you tell the IRS that you met the 2018 RMD requirement. Keep good records in the (unlikely) case that you get an IRS inquiry letter.

[SweetieJean]

Answered in comments.