𝗨𝘀𝗲 𝗕𝗶𝘁𝗿𝗶𝘅𝟮𝟰 𝗶𝗻𝘁𝗲𝗿𝗻𝗮𝗹 𝘀𝘁𝗼𝗿𝗲
The main advantage of this way – it's easy to create and configurate.
However, internal Bitrix24 store has limited functionality and page design difficult to customize. In addition, using the Bitrix24 internal store you‘ll have no access to code. So, this way is more suitable for small online stores and creating landing pages for testing hypotheses.

𝗨𝘀𝗲 𝗕𝗶𝘁𝗿𝗶𝘅 𝗖𝗠𝗦 𝗳𝗼𝗿 𝗼𝗻𝗹𝗶𝗻𝗲 𝘀𝘁𝗼𝗿𝗲
Also, you can use Bitrix CMS for your store – it can be fully customized and simply connected to Bitrix24 in the cloud. If you create a store on Bitrix CMS, you can easily integrate it with Bitrix24: all orders will automatically enter to CRM. You will be able to automate order processing, work with customers faster and never miss a single incoming request. So, this way is best for any, even most complex, online stores but it's pretty expensive.

𝗨𝘀𝗲 𝗪𝗼𝗼𝗖𝗼𝗺𝗺𝗲𝗿𝗰𝗲 𝗳𝗼𝗿 𝗼𝗻𝗹𝗶𝗻𝗲 𝘀𝘁𝗼𝗿𝗲
You can also create online store on WordPress using WooCommerce plugin and it also can be integrated with Bitrix24.
WooCommerce is e-commerce extension for the WordPress CMS. It has wide functionality and now it's a most popular plugin for creating online stores. One of the main advantages of this way – WooCommerce is free, but its setup and further customization can take a time and money. This way is suitable for creating new online store as well as connecting order and payment options for working sites on WordPress.