There are many answers, based on the intensity of laughter you want to express, and even the level of crudeness.
The standard is LOL (laughing out loud)
It can be added to any sentence to give it a funny undertone lol!
ROFL, is more humorous, meaning Rolling On Floor Laughing
You would normally respond to a funny comment with ROFL! (Single word and exclamation mark)
Then there is LMAO! Laughing My a$$ off. Self-explanatory.
Rolling on the floor laughing my A** off.
Rolling On Floor Laughing Out Loud
Are you sure you don't mean ROFL - which is Rolling On (the) Floor Laughing.
Laughing On the Inside or Letter Of Intent or Letter of Insurance. It depends...
The type of expression that would be meant by the internet slang "lmao" is a reference to one laughing. The expression means "laughing my a** off". It is sometimes said "lmbo" which means "laughing my butt off".
It is probably a misspelling for ROFL or ROFC, which means rolling on the floor laughing or rolling on the floor crying.
In Internet slang, it can stand for "In My Arrogant Opinion". Unless you mean "LMAO" Which would be "Laughing My ass Off"
RTMFL is not considered to be an Internet slang for anything. ROTFL stands for rolling on the floor laughing and RTFM stands for read the flipping manual.
The most common use of LOL is Laugh out loud.
TOL stands for thinking out loud. It is an internet slang word that is an acronym of TOL. It may also mean thinking out laughing. That is the definition of TOL.
"lol", an abbreviation for laughing out loud, laugh out loud, or sometimes lots of laughs, is a common element of Internet slang. Made in the 1990's.
LMAO is an internet slang term that means "Laughing My A** Off."LMFAO is a more emphatic form.LAMO may be a typo, or mean "lame-o" (a foolish or inane person).L'amo is an Italian term for la amo (I love her).