Direct questions are the "normal" questions that we can ask friends, family members, and people who we know well.
Direct questions follow the normal word order (question word) + AuxiliaryVerb + Subject + main verb.
Where is the bathroom?
Use indirect questions when you want to be more polite.
Use them when talking to a person you don't know well, or in professional situations.
In an indirect question, forms are a little different, the word order is Subject - Aux verb.
Could you tell me where the bathroom is, please?
Normally indirect questions begin the question with expressions such as
Can you tell me...
Could you tell me...
Do you know...
Would you mind telling me...
I was wondering...
Do you have any idea...
I'd like to know...
Would it be possible...
Is there any chance...
In Embedded questions, with is/are, the verb (is/are) comes after the subject.
Direct: Where is First Street?
Indirect: Could you tell me where First Street is?
In embedded questions, we don't use the auxiliary verbs do/does/did.
Direct: What time does the bank open?
Embedded: Do you know what time the bank opens?
There is no auxiliary verb did in the indirect/embedded questions.
Direct: Why did you move to Argentina?
Embedded: I was wondering, why you moved to Argentina?
To form the indirect question, remove does and change "cost" to "costs".
Direct: Direct: How much does this book cost?
Embedded: Can you tell me how much this book costs?
If the direct question is a "yes or no" question, then the indirect/embedded question will have if.
Direct: Does Tom like Thai food?
Embedded: Do you know if Tom likes Thai food?
Direct: Are your parents joining us for dinner?
Embedded: Could you tell me if, your parents are joining us for dinner?