What is the correct and why?

[truelove.ksa]

It was a great idea.
It is a great idea.
Which one is the correct and why, I’m trying to enhance my writing.
Thank you all : )
Please if you remark anything about my writing let me know.

 

[emsr2d2]

Depending on context, they are both fine. The only difference is the tense.

 

[Rover_KE]

Welcome to Using English, truelove.ksa.:-D

A better thread title would have been 'It was/is a great idea'.

Please read the Posting Guidelines, especially this one:

Thread titles should include all or part of the word/phrase being discussed. (Avoid phrases like "HELP!", "Urgent!", "translation please", "how do I say this", "I'm new" and similar expressions.)

Rover

 

[Tdol]

It was a great idea. (Two years ago)
It is a great idea. (Now/Always)