Hi @ajur ,
Yes, it is possible! You can enable custom component switching to design mode at the upper right corner of the page.
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Click to setting icon and select component which you want to enable it on the page.
Also, /libs/settings/wcm/designs/default/jcr:content/teaserpage/par this is the right path where components are allowed.
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You can also create your own template either by extending existing template or copying and customizing it, as we follow traditional way of AEM component/template development.
Hope that helps!
Regards,
Santosh