Autocomplete
A flyout/menu appears when the user starts typing to suggest tags that are supported or have already been entered previously.
Sometimes tag field can be additive, meaning new tags may be added from this particular tag field. They can also be restricted to only allowing tags that already exist in the system
Overflow
When there are more tags than fit in the horizontal space, tags wrap to another line.
Focus between tags
If the order of tags within the group matters, the user must be able to click or use keyboard focus between tags to add more.