In addition to the start-geopoint question - to capture an initial location when you first start the form, you can also take subsequent periodic location snapshots in response to, say, answering a question. See https://getodk.github.io/xforms-spec/#setting-a-static-value-when-a-nodes-value-changes for an example of what this looks like.
Please note, this feature is not yet exposed in XLSForm per se, so it requires manually editing your XForm to add it. There is an open feature request to additionally expose this in XLSForm, and a lengthy discussion in the Forum about it here.