This is a style issue. It used to be necessary to use two spaces after an end mark, with typewriters and whatnot, but that's not a common problem anymore. Some people think it gives the period (or question mark or exclamation mark) more finality, and some don't care. It's up to you.
In traditional English writing, there are two spaces after a period.
How many spaces do you need after the word period? Is she having her period.
In journalistic writing, only one space. In all other writing, two spaces.
Some put two (or even three) spaces after a full stop (period in America) before starting a new sentence. One space after a comma. Personally, I use two spaces, unless I forget!
It is recommended to use only one space after a period before starting the next sentence. This standard has become widely accepted in modern typography and word processing.
2 Spaces
In typing, proper style is 2 spaces after a period (.), as well as after a colon (:).
It used to be 2 spaces but nowadays it is only 1.
2
2
When I grew up, every period was followed by 2 spaces. However, I have heard they changed this to 1 space.
You press the button 2 spaces from the right of the M.
no spaces
In traditional English writing, there are two spaces after a period.
one
one space after and abberviation two spaces at the end of a sentence
One space follows a period after an initial.