Anchor is your friend.
If you look you will see that all the controls have an anchor property. Anchor fixes the distance from the border of the control to that side of the parent (The form usually).
For default controls are anchored to the top and the left, meaning they will maintain the distance to the top and the left borders of the form, and ignorin if it gets big.
If you anchor somehing to the bottom and rigth it will stay at the same distance from the rigth and botton borders, moving when you resize the form. Thats usefull for when you need something in the down right corner (An accept button, for example)
Now the interesting part is that if you anchor something to two oposite sides (top and bottom or right and left) it will maintain its distance to both borders. And what happens if the borders distance themselves? the control grow.
So you need to play with it, see what controls do you want anchored where, wich one to grow and wich ones to stay still.
In your caseI would set the labels to be anchored top and left and the textboxes to be anchored top, right and left. So they will expand to the right when the form is resized.