What is targeted advertising on Instagram and why do you need it?

What is targeted advertising and why do you need it?
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First I will explain the meaning and the basics, more to come✌

Targeted advertising is Instagram's official advertising.
In general, it was originally made for selling. The number of followers is the main thing, but it needs to be reinforced, and targeted advertising is perfect for strengthening an account and raising sales.
Only through the "Promote" button inside the Instagram account itself.
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Only here is there an active link to the profile itself. In the Facebook business account you can only add a link to a browser, and there you cannot subscribe directly.
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But there is a way out: you need to mention the profile in the text several times.
Optimally 2-3 times. At the beginning and definitely at the end, with the specific call to action you need.
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It is much better to set up ads through Facebook. But you always need to look at the goals of the ad campaign.
For example, for gathering followers it is cheaper for me to promote directly in Instagram.