Login using yourmyshopify.comURL and follow the next couple of prompts from there.
If you're after a custom app for your store, I would recommend taking a look at our Shopify Expertslistings as you can filter according to your own budget, location etc.
Is there a particular app you're after?
Nia | Social Care @ Shopify - Was my reply helpful? Click Like to let me know! - Was your question answered? Mark it as an Accepted Solution - To learn more visit the Shopify Help Center or the Shopify Blog