issue regarding values in textbox

If I am designing a login form in construct 2, Then for one text box how I will come to know that user has finished entering the data in that text box so that we can give any action that must be done after entering the values in that particular text box.

TextBox > On text changed

There is no option for "on text change" for TextBox

There is. If you don't see it listed when you try to add a condition then my guess the current event already has a trigger or it's a sub-event of a trigger.

https://www.scirra.com/manual/117/textbox