Is it possible for the player to enter his own name at the beginning of the game and then when he enters, for example, the collision box or when he interacts with AI, the name that was entered before is displayed?
(if you did not understand me I apologize but I am using translator)
Yes, you can. You need to create a widget with a input text box, then add the widget to the viewport.
Once the player put the name, save the content of the input box in a variable, in the character blueprint, (or in the gameinstance blueprint in case you need the name to persist between levels)
One you got the name in the variable, you can print it when you want it, using another widget with a text box.