Variables in Issues or tests

Hello everyone,

we are using Jira at work and we oft we have the problem that, for example, if a name or something has to be changed on the issues or tests, we have to do it manually for all the thousands issues that we have write. For example. we use a name for a product (NIKISA) and we have it as title for many issues (NIKISA Bug in first floor) etc. Let's say that we have to change the name (NIKISA) to all the issues at once. How can we do it ? Now we are opening all issues one by one and we change it manually.