I have created a custom theme which i inherit from the blank theme, if i applied third party extension its not applied, i am tried with couple of extensions same issue, what are all the necessary steps to follow for install a third party extension in custom theme
There is no different way to install extension for custom theme or for default theme.
First upload your extension in app/code/ folder
Run below commands in CLI to install your extension
bin/magento setup:static-content:deploy -f
chmod -Rf 0777 var/ generated/ pub/
After that please check in config.php file(app/etc/) to check that your extension is installed or not. You can check it with your PackageName_Module
Please follow above steps and let me know if you have any query.