Can you all tell me exactly how a breakthrough is written. Is there like some sort of mental thing or is just like that?
Need this information for the future.
Your question is vague at best.
If you mean a cultivation level breakthrough (from Qi Condensation one to QC two or from QC MAX to next level Foundation Building), it is both a mental thing and a physical thing.
Think of it like you are lifting a weight heavier than what you would usually do.
If you don't lift weights, you can also visualise doing a tough task like you usually wouldn't. Using me as an example, talk to a woman and hopefully woe her.
The task will be arduous, filled with obstacles seen and unseen and you have very little reaction time to correctly deal with them. And this is the physical aspect.
The mental aspect is to maintain a cool and collected mind and keeping your concentration up as long as possible, which is hopefully for the task to succeed.
In cultivation terms, a breakthrough is when the body has evolved (able to lift greater weights in future) and the possible obstacles can be the physical qi going too fast, too slow or even the wrong direction. The mental aspect would be testing the person to not panic and keep his head in the game.