View Controller content isn't showing

Hi I'm new to swift and I have the following problem:

My project has a Tab bar menu that, when clicked, calls different Viewcontrollers, when I click on the menu, only the related title, and color that I determined appear, but the main content that I placed such as label, buttons, etc... does not appear.

I'm not using storyboard just doing everything by code inside each view controller. What did I forget to do?

I fixed thanks

Great. But when you ask question, please show the code. Otherwise it is just a question for yourself, not the forum…

View Controller content isn't showing
 
 
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