How To Inject The Main-Product.Liguid File Automatically.

[subho]

I have an online store connected to Shopify. My merchant need to enable "personalization" for their Shopify store. Currently, each merchant is manually editing the product.liquid file for personalization. While there are personalization apps available, they are paid options. Therefore, I am exploring ways to automate this process. Is there a way to inject the Shopify theme, specifically the product page, automatically? Are there any APIs available for this feature?