You can import tasks from Jira Cloud Software by clicking the "Import tasks" button on the top of your tasks or by right clicking on a task and selecting the "Import tasks" option.
Select then "Jira" in the list of import options, enter your Jira sire URL, your Jira login email, your API token and click "Connect to Jira". (see below on how to find these information and create your API token)
Once done, you will be asked to select your Jira's projects you want to import. Select the projects you want to import and continue.
If your Jira projects contain Team members assigned to tasks/issues, you will be asked to match them to existing team members, create new ones or ignore them.
Once done, just select the destination of your import and finish your import.
Finding your site URL
Your site URL is the URL that appears when you are connected to your Jira software and that looks like https://YOURSITEURL.atlassian.net
Create your API token
In order to create or find your API token, go to your Jira "Account settings" (⚙️icon on the top right) and then in the "Security" section.
In the "API token" section of the page, click "Create and manage API tokens".
Click on "Create API token", enter a label and then copy your token.