"Why it is" vs "Why is it"

What is the difference between these two sentences:

1 ) Please tell me why is it like that. (should I put question mark at the end)

2 ) Please tell me why it is like that. (should I put question mark at the end)

1) Please tell me why is it like that. [grammatically incorrect unless the punctuation is changed.

Please tell me: Why is it like that?

The question: "Why is [etc.]" is a question form in English:

• Why is the sky blue?
• Why is it that children require so much attention?
• Why is it [or some thing] like that?

When that form is put into what is called indirect speech, it becomes:

• Please tell me why the sky is blue.
• Please tell me why children require so much attention.
• Please tell me why it's like that.

The question form becomes a statement and therefore, the clause must follow the subject + verb rule for a declarative sentence with no subject and verb inversion.

2) Please tell me why it is like that. [correct]

Please tell me why [etc.]is not a question. Therefore, it would take no question mark. You can see that the first three examples above are questions and take a question mark at the end.