Exactly as you have done in your question.
PTA should be punctuated with periods as an abbreviation for Parent-Teacher Association.
It means to place periods, commas etc in your writing.
It means to place periods, commas etc in your writing.
The abbreviation for excetera is etc.
It would be correct to do so. It would be better to try and not use the abbreviation at all and to define whatever else is similar
THey should be placed in parentheses
The city, ST ZIP line should be punctuated as follows: City, ST 12345 Name of city followed by a comma and one space. Then 2-letter state abbreviation followed by 2 spaces before the ZIP code.
There is no universal abbreviation. It should be spelled out.There is no universal abbreviation. It should be spelled out.There is no universal abbreviation. It should be spelled out.There is no universal abbreviation. It should be spelled out.
etc.
The abbreviation for et-cetera is etc.
Yes, "R.S.V.P." should be punctuated with periods between each letter to indicate that it is an acronym for "Répondez s'il vous plaît," which is French for "Please respond."
Etc,etc