Hi Jan,
Good question.
To add the multi-line data entry option to a text tag, simply use the following Text tag: {{largeField_es_:signer1:multiline}}
You can also specify the number of lines you'd like the text to occupy by including it in the text tag in brackets, i.e. 5 as can be found in the following example: {{largeField_es_:signer1:multiline(5)}}
Please note that you can also extend the space a field occupies by spacing out the closed brackets. The 2 following text tags will occupy space in the following way:


For more information, please find our Adobe Sign Guide for Text Tags here outlining the various options available.
Hope this helps!
Kind regards,