Example:
引っ越す
引っ越しします
I know they have the same meaning but what are the small details? I remember seeing the structure お+verb stem+する used in humble speech, but here the お is omitted.
Example:
引っ越す
引っ越しします
I know they have the same meaning but what are the small details? I remember seeing the structure お+verb stem+する used in humble speech, but here the お is omitted.
You are confusing a noun for a verb.
In school grammar, this is called 連用形の名詞化 (nominalization of te/masu-form). 引っ越し is certainly a masu-form, but it can also be a noun on its own. (BTW 引っ越し can't be called a stem; its negative form is 引っ越さない.)
The complication is that not all verbs can be turned into nouns in this way, and you must look up dictionaries whether or not it is an accepted nominal form.
For example, the equivalent to above of 起きる is 起き, but this by itself is not a noun and ×起きします is not acceptable. On the other hand, 早起き is a totally common word and 早起きします means (I) wake up early.
This contains a bit more details.