So, first of all, you need to find your target audience and use that social media channel which has a large number of your target audience this will help in increasing sales.
Facebook seems to be the most suitable for conversions, however, Instagram is beginning to gain momentum with its shopping features. Whether to use Facebook or Instagram depends on the nature of your business and the type of products you sell. You have to make sure you work hard and never leave your social media unattended.
Social networks are not for sales but it is best used to listen to your customers, spreading awareness, brand recognition which ultimately helps you to boost your reach and sales. Use social media to understand your buyers and try to engage with them on a regular basis. These efforts will help you to attract more potential customers. Engage them to convert those visitors to leads and sales. Thank you.
Your social platform is dictated by your buyers and prospective buyers not by opinion or modeling what other companies use. Sometimes it can be more than one platform, but in my experience, one particular platform always seems to be better than the others for each company I’ve worked with.
In a previous recommendation, I referenced building customer personas, and it couldn’t be more poignant here… Establishing what your customers look like and knowing their behaviors is paramount to this decision.
A buyer persona is a semi-fictional representation or model of your ideal customer based on market research and real data about your existing customers. This is not something that should be guessed at or assumptions made based on what you believe to be true. Significant research is required and best handled by a third party.
When creating your buyer persona(s), consider including customer demographics, behavior patterns, motivations, and goals. The more detailed you are, the better.
Check out this link from HubSpot, it should help you in the development of your buyer personas.
I've worked in this realm for quite a few years now relating to service sales and have found Facebook to provide the most positive traffic and leads and this is without FB advertising but rather, being 100% social campaigning. That's my experience at least. ;)