Just remove the class atribute and and add size="10", it should look like this:
<input id="$customField.id" name="$customField.id" type="text" value="$textutils.htmlEncode($!value)" size="10"/>
Just change the number 10 with the number of caracters you want to show up.
I belive this documentation will help you achieve what you're looking for: https://confluence.atlassian.com/display/JIRA/Changing+the+Size+of+the+Text+Area+Custom+Field
Let me know if this information helps you!
Hey Community mates! Claire here from the Software Product Marketing team. We all know software development changes rapidly, and it's often tough to keep up. But from our research, we've found the h...
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG
You're one step closer to meeting fellow Atlassian users at your local meet up. Learn more about AUGs