I need to add a custom text field to our tickets for the developers to enter their solution
Your question is unclear to me. Where do you want this new custom text field? In the creation of the issue?
https://confluence.atlassian.com/adminjiraserver/adding-a-custom-field-938847222.html
https://confluence.atlassian.com/adminjiraserver/defining-a-screen-938847288.html
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