By multiple tags on an xNT I guess you mean, multiple NDEF records?
Some apps will show all of them, like NFC Tools or NXP TagInfo. Some apps just default to show the first record, or the last record. We’ve seen an app on iPhone default to show text records for some reason, but other records are available if you go into ‘More…’
So basically, it’s up to the whim of the app dev how each app handles multiple records per tag.
To further complicate things, NDEF records are stored inside NDEF messages, which you can also have more than one per tag. So multiple messages, each containing multiple records.
Again, up to the whim of the app dev how their app handles that. But usually, the default is first message, first record. So put the important information in the first record, cos that’ll probably be seen most often.