Solution:

I am ERROR

Solution:

The word is Energy.
Nobody said anything about the order of 'g', 'r' and 'y' at the end of the word.
Also, we use energy every day.

Solution:

I am number 7 on any phone's number pad.

Solution:

Paradise

Solution:

Mississippi.

(For example, One Mississippi, Two Mississippi, and Three Mississippi etc.)

Solution:

CITIZENSHIP

Solution:

Password

Solution:

Mountain

Solution:

I am DAVID.

At the core I have 5
If we talk in roman numeric system, 5 = V

Similarly, 500 stands in the beginning and end
500 = D

I also include the first letter i.e. A and the first number i.e. I (in roman numeric system)

All of them combine to form DAVID.

Solution:

Chair.