It's not clear whether you're trying to conditionally display another field or just the contents. Then there's the question of what you mean by 'field' - which for all I know could be a content control or formfield.

For some of the issues you might need to deal with, including the above, see:

Fillable Forms:
https://support.office.com/en-us/art...B-AC44937E3A9F

Conditional Insertion of Additional Formfields:
https://www.msofficeforums.com/word/...b-question.htm

Dependent Dropdown Content Controls:
https://www.msofficeforums.com/word-...html#post77762

Hierarchical Dropdown Content Controls:
https://www.msofficeforums.com/word-...html#post94603

Dependent Text Content Controls:
https://www.msofficeforums.com/word-...html#post46903

Dependent Text Formfields:
https://www.msofficeforums.com/word/...html#post46429

Content Control & Formfield Conditional Formatting:
https://www.msofficeforums.com/word-...html#post47254

Creating and Tallying Mutually-exclusive Checkbox Content Controls:
https://www.msofficeforums.com/word-...html#post33489
https://www.msofficeforums.com/word-...tml#post107008

Replicating data in a form:
http://gregmaxey.mvps.org/word_tip_p...ting_data.html

Adding a new row to a table in a document with formfields:
https://www.msofficeforums.com/word-...html#post38312

Adding a new row to a table in a document with content controls:
https://www.msofficeforums.com/word-...html#post87989
https://www.msofficeforums.com/word-...html#post38461

Do note that formfields and content controls were not designed to work together and generally should not be used in the same document.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]