Yes, we do offer installation services for all of our modules. You can check the installation price of every module on the product page of the store.
Also, you need to provide the following details to initiate offer installation services :
Order ID (Purchase Receipt)
FTP host URL or IP of the site (SSH details in case of Magento 2)
FTP Path of your Magento/Opencart installation like (/opt/bitnami/apps/magento/htdocs/)
If you have purchased the extension and forgot to tick the Installation checkbox on the product page.
After this, you can still make the payment for the same and kindly follow the steps as mentioned in the below knowledgebase :