Check in the specified file

• command: spo file checkin -w|--webUrl <webUrl> -i|--id [id] -u|--url [url] -t|--type [type] -c|--comment [comment]
• webUrl: The URL of the site where the file is located
• id: id of the file to check in
• url: server- or site-relative URL of the file to check in
• type: type of the check in. Available values Minor|Major, default Major
• comment: comment to set when checking the file in
• specify either the ID or the URL of the file to check in but not both
• requires connection to a SharePoint site

For more information see the Set-PnPFileCheckedIn cmdlet