In Agile Poker for Jira Cloud you can estimate only issues that estimation field is set as valid for the right issue types. If some issues (e.g. bugs, tasks) are not visible in Agile Poker for Jira it means you have to add an estimation field (for example Story Points) to the relevant issue type.
Adding the estimation field to custom issue type
It might happen that you don't see all desired issues in the estimation scope of Agile Poker. For example, Bug issue type doesn't have the Story Points field by default.
You may also need to add Story Points field to relevant screens sometimes the Field Configurations may also be hiding the Story Points.
Configuring Ogirinal estimate time field
In order to estimate a time field like the Original estimate, a configuration similar to the one above needs to be done.
However, there is an extra step that needs to be done: adding Time tracking to Issue screens. Unlike other fields, you won't see the Original Estimate in the list because it is managed by a larger Time tracking group of fields. It's possible that the Original estimate is present in your issue details and you can edit and save it, but it might be not available for Agile Poker if the Time tracking is missing from the appropriate Screen.
In order to ad the Time tracking to a screen, navigate to Jira settings → Issues → Screens, choose a relevant screen, edit it and add the Time tracking to the list:
Alternatively, open issue details for the issue you want to estimate, click on Configure from the bottom right:
and click on the screen mentioned on the Issue layout page to get to the corresponding Screen.
Managing fields visibility