I am planning to study MBA in germany but I think about to do the first semester and then start studying german language course in the second semester and during the second semenster I will postpone studying MBA untill get well in the german language

My question is can I do that or I will need to change the vise or do something regarding the visa issues .

No, you cannot do that with an accredited full time MBA. Learn German first. Ask the business school you want to attend about the language schools or Studienkolleg it works with.

Yes, you can take German classes in Germany, and if you take a course that fulfills the requirements, you can get a 'language learning' visa for the duration of the program. Do that first and then start the MBA.