It's possible to move to the next field if a certain number of characters have been entered. Is that what you mean by "filled"?
First make a document level script and put this into it and name the document script AutoTab:
function AutoTab(doc, event, cNext)
// Call the built-in routine to allow numbers only.
AFNumber_Keystroke(0, 0, 0, 0, "", true);
// If we've filled in the field completely, jump to the next one.
if (event.rc && AFMergeChange(event).length == event.target.charLimit)
Second you will need to place a limit of characters in the text fields. (i.e. 9 fields for a Social Security Number, set each field limit to 1 character on the options tab in properties) Also, name each field SSN1, SSN2, SSN3, etc.....
Third: Go to the FORMAT tab and select CUSTOM in the drop down list and place this into the CUSTOM KEYSTROKE SCRIPT box (This is for the first field named SSN1):
AutoTab(this, event, "SSN2");
Fourth: You will need to place AutoTab(this, event, "SSN3"); AutoTab(this, event, "SSN4"); and so on and so forth until you have mapped SSN8 text field to SSN9 field.
Hit preview, start in the first box type 1 number and it should automatically go to the next field.
I did not create this script. I got it from this site. I would cite where I got it, but I couldn't find it. So credit is given to the one who created this.
OMGosh thank you! I had been searching for creating auto-tabbing fields in Acrobat DC and found this: Auto Tab the Next Field
but I needed the Document Level Script bit (not familiar with this) you had here . . . (am new to interactive form building AND Acrobat DC) . . . and it now finally works! Yea, I'm happy so needed to thank you.