Change the narration: "Will you be home soon?" she asked her husband.

She asked her husband would you be home soon.

She asked her husband if he would be home soon.

She told her husband will he be home soon.

None of these

She asked her husband if he would be home soon.

"Will you be..." (direct question) changes to "if he would be..." (indirect speech).

The question form becomes a statement in reported speech, and "will" changes to "would."