Trying to find a way to grab the first 10 characters of a multiline field in a list and use it to populate a single line field in a list.
do you work with responsive or classic form design?
in responsive form you could do that with 'set value' rule.
could you provide more details how should it work?
do you need it just on form load? or triggered by an event/action (button)?
do you need it in NEW and/or EDIT form?
multiline field is just a plaintect or reach text?