To change the length of the text used in this project, you would also need to change the dimensions of each comp used to hold the text. So for example in "BLOK 1" there is a comp called "Text01" that is 1576x500. If you want to make it longer you can (using the Composition --> Composition Settings menu item), but then you will also have to adjust the animations in BLOK 1.
E.g. here I have replaced the first word with "length" and the letters "g" and "h" are cropped:
If I change the width of the comp to 1676x700, it is no longer cropped:
But if I go back to the BLOCK1 comp, the text no longer fits nicely into the boxes:
So you would have to adjust the animation on"Shape Layer 1".
If you select the layer and press u you can see it has some animation key frames on it - it is a straight line which changes length and stroke width (thickness of the line):
After a while it becomes easier to make your own animations than it is try to tweak other people's.
I highly recommend this free course to get to grips with the basics of After Effects that you would need to continue tweaking this project.