Without seeing your footage and your tracker settings nobody can answer any of that. Most of the time this is simply user error by choosing unsuitable settings or having shot the footage wrongly in the first place. Not every shot can be 3D-tracked.
Maybe this very short tutorial will help:
Thank you, finding the right tutorials is challenging at times, in this case the reason my text was being created so far off screen was due to normal text creation using the previous settings which had quite a few adjustments, which in 2D was not an issue, but when in 3D put them off into space. Also resetting the scale and then using Text size put things right.
The other very frustrating issue I still can't get correct is lighting and shadows, I suspect it's also a setting I'm overlooking. I can't seem to get shadows to cast correctly. Even creating and following very simply tutorials, my shadows are way off. In the screen shot below, the ONLY shadow I get is either as you see it there or none at all. Adjusting positions, the shadows "pop" full length or disappear altogether.
I've tried every position and type of light I can think of but don't understand why the light is behaving this way much less how to fix it. I suspect I must have adjusting something along the way and can't figure how to reset it.
I'm switched from point to spot to manipulate the light, there is one other ambient light active aside from what you see here. Using any falloff setting other than NONE results in the shadow disappearing. The shadow is ending where the shadow catcher ends in this case. Seems like it should be a very simple fix.