If you see all the Properties of Form in VB.NET, you will find WindowState Property.
Set this property value to Maximized your Form will be open with FullScreen Mode.
Or you can do the Same thing from Code. Write the Following Code on Form Load Event:
Private Sub Form1_Load( ByVal sender As System. Object , ByVal e As System.EventArgs) Handles MyBase .Load Me .WindowState = FormWindowState.Maximized End Sub
I hope it will help you. :) Here two nice articles with the solution:
Fullscreen the form in VB.NET using a class [ ^ ]
How To Make a Windows Form App Truly Full Screen (and Hide Taskbar) in C# [ ^ ]

Read the question carefully.

Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.

If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.

Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question. Let's work to help developers, not make them feel stupid.