I am invested in a 401 K but I dont know how much I made in it for 2019, does this need to be included in filing?

[thisistheusernam]

I dont know what I did with the paper that tolkd me how much I made

[SteamTrain]

IF you didn't actually take any money out of the 401k, then the gain-or-loss in the account value  for the year is just an FYI they provide so that you can think about whether you want to change you investment mix.

The prior year's, year-end value is only critical for a year in which you reach age 70.5, and the years after, so that you can determine the RMD (Required minimum distribution) that you must take out of the account every year after reaching that age ..... but if you haven't already reached age 70.5 by some date in 2019, that age has been changed to 72 for future years.

[VolvoGirl]

How much you made or how much you contributed or how much you took out?  You only enter 401K contributions from your W2.  You don't enter any interest, dividends, buys or sells or values inside the 401K.  And you don't report loans unless you leave and don't pay it back.

You only report distributions, withdrawals, rollovers, Transfers to another account or conversions.  You will get a 1099R for those.