One space is sufficient.
It's usually a matter of style though. If you decide to use two spaces then you should be consistent with this throughout the rest of your work.
In standard prose typing, you space twice after a period.
Once. The only time to use more than one space is after a period.
You put the right quote immediately after the period and then 1 space.
Once. That is enough.
Two times
Are we talking of Menstrual Periods, or Grammatical Periods. ????
No, just use one space.
It's a text string formed by typing the digit ' 1 ' twenty-three times, with a space between the tenth and eleventh ones.
If there is more than one initial, there is no space after the period which separates them. After the period after the last initial there is one space.e.g. T.S. EliotAfter a period at the end of a sentence you do two spaces, but often only one is done.
8250 You move the period 1 space to the right for every 0
Typically, you would hit enter once after typing the address before typing your greeting. This creates a line break, allowing for a clear separation between the address and the greeting. If you're following a specific format, like in a formal letter, you might hit enter twice to add an additional space.
Normally two spaces indicates the end of a sentence.