In Infigo Designer templates, you are able to configure your text fields to automatically increase or decrease their font size to ensure that the entered text will fit the field best. You are also able to set a minimum and maximum font size for your text fields which have this feature enabled. This will allow you to have your field's font size automatically adjust to ensure that all of the text is visible within the field, whilst ensuring that the font sizes remain within a reasonable range.
To do this, simply open up your template in Adobe Acrobat (ensure that you have Infigo Designer installed before proceeding).
Next, select the Select Field Entries tool (highlighted in the screenshot below) and double-click the text field you wish to configure this for.

In the Field Settings menu which pops up, navigate to Text Settings > Standard Format. You will see a checkbox with the text Fit Box beside it. Enabling this will also allow the Fit Box Options to be configured.

Enabling Fit Box will enable the feature, however you can control how it acts using the Fit Box Options below:
Allow Wrapping - This will determine whether the font will grow/shrink so that each line of text remains within its own line, which will likely force your text to shrink to a smaller value, or whether it will allow the text to wrap within the field and simply change the font size so that the text fits the box.
Set Limits - This will allow you to set minimum and maximum sizes (measured in points) the font is allowed to shrink or grow to when fit to box is enabled. If the font remains too large to fit within the box when it is at the smallest allowed size, then any excess font (most frequently the last characters/words) will not be displayed as they will be outside the field.
- Min - This is the smallest size the font will be able to shrink to
- Max - This is the largest size the font will be able to grow to