"She is invited" is a statement of fact. "She is being invited" is a current action, happening now, in the present. "She was invited" is past tense action, happened in the past. "She was being invited" is really difficult because "was" is past tense and "being" is present. Usually we use that form when we want to describe a particular action that happened in the past. For example, I was going to the store when I discovered I forgot my list and had to go back for it. I hope this helps. We would say, "I would be thankful if you would help me to understand these sentences." or "I would appreciate your help to understand these sentences."

She is invited. Generally this would be used to describe her current status "invited" She is being invited. Although it is the present gerund, this could equally be used as future tense e.g. I've not asked her yet but she is being invited She was invited Past tense e.g. I haven't seen Mary here. She was invited. She was being invited. Imperfect? She was being invited to the party when her phone rang....

They are all correct. She IS invited means there is an event that she is welcome to go to. She is BEING invited - means that it happening right now, in the present someone is inviting her now. She WAS invited - means she got the invitation in the past. She WAS BEING invited - I would not use this as it is a odd verb tense. It's in the past "was" and active now "being". It's like saying - I was working - which means at some time in the past I was working. But it doesn't really apply well here.

They are all correct. They have different meanings as I was trying to explain. It would depend on the question. Sorry I missed the question in the title.

Sorry, for my mistake. .... On title is, Which sentence is correct?