The ODK ecosystems use XML form definitions following the ODK XForms specification, a subset of the W3C XForms specification. You'll need to convert an XLSX file using one of the ODK tools, not just save from Excel to XML format. You can test a form using https://getodk.org/xlsform/. There's a great deal of detail on authoring forms in the documentation:
Welcome to the ODK forum, @yogita_karpate! We're glad you're here. When you get a chance, please introduce yourself on this forum thread. I'd also encourage you to add a picture as your avatar because it helps build community!