L
The letter "R".
The letter E would be at the vertex. The two lines enclosing the angle E would be ED and EF. Usually, to make it quite clear we would call angle E by the description "angle DEF or angle FED (they are the same angle).
a
it has a right angle in there
It is an angle that on both sides it has a right angle
They can make an obtuse angle, a straight angle or a reflex angle.
It could be capital letter A
An angle can be named with one capital letter.
There are no angles in the letter l it is a straight line That's not right. There is one angle in the Letter l. its a 180 degree angle.
an acute angle
If you mean which alphabet letter, an L has one right angle; a T has a right and left acute angle.