Does Store Credit & Refund extension support to refund to store credit when we create credit memo?

Yes. When you create new credit memo, you can refund payment to store credit.

Also if you create new order manually, you can use customer credit balance for order too.

{{widget type="Magento\CatalogWidget\Block\Product\ProductsList" show_pager="0" products_count="10" template="product/widget/content/grid.phtml" conditions_encoded="^[1:^[type:Magento||CatalogWidget||Model||Rule||Condition||Combine,aggregator:all,value:1,new_child:``^],1--1:^[type:Magento||CatalogWidget||Model||Rule||Condition||Product,attribute:sku,operator:(),value:SCR,SCR2^]^]"}}

General Questions