No spoiler alert - What am I?

Question

Here're some of my properties:

1. People usually put a hole in front of me, I do not know why.  
2. Some refers me as Delend, but that's not my name.  
3. Inverted, I might have shown myself.  
4. I might be small, but once shifted, I became invisible.  

What am I?

Hint 1:

By giving out a hint I'm almost giving out the answer, right here.

Answer 1

The answer is

.1

Because

"." is below ">" and "1" is below "!" combining the 2 creates the spoiler block quote.

People usually put a hole in front of me, I do not know why.

with .1, most people place a 0 before to make 0.1 - As shown in answer by Bass

Some refers me as Delend, but that's not my name.

Del is on the "." button on the number pad. End is on the "1" on the number pad.

Inverted, I might have shown myself.

For List point 1., if you would have written ".1", then you would have shown the answer right away.

I might be small, but once shifted, I became invisible.

using the shift key while pressing ".1" on the keyboard creates the spoiler block quote.

Answer 2

Are you

the numpad decimal point?

1. People usually put a hole in front of me, I do not know why.

You can write a

zero in front of positive numbers smaller than one, that is, 0.05 and .05 are the same number.

2. Some refers me as Delend, but that's not my name.

"del" and "end" are words that are found on numpad keys. Maybe there's a layout where they are both on the decimal point?

3. Inverted, I might have shown myself.

Not sure about this, might have something to do with the inverted comma?

4. I might be small, but once shifted, I became invisible.

The decimal point is very small pixelwise, but if you press shift, you get the unprintable "del" instead.

Answer 3

Possibly

the numpad '0' key (alternate 'Ins')

Reasoning 1:

the key is typically separated from the arrow keys by a gap ("hole") to its immediate left

Reasoning 2:

the key is located just below 'End' (the alternate for numpad '1') and to the right of 'Del' (the alternate for numpad '.'), i.e. 'Delend'

Reasoning 3:

This could either refer to the fact that 0 is its own additive inverse (-0 = 0), or to the fact that the 'Ins' key inverts the status of overtype (on-to-off, off-to-on) in most applications, and hence is its own inverse

Reasoning 4:

the number 0 is small, but when the Shift key is held down (the key becomes 'Ins'), it produces no visible character when pressed