As a brand or as a business, several points must be taken into consideration when it comes to choosing an influencer. First, it is important to know your main business objective. If you want to gain notoriety, it would be interesting to reach out to a wide and varied audience, with a macro-influencer, for example. If your goal is to convert future customers to purchase, it would be more interesting to partner with a nano or micro-influencer in order to properly target your audience and benefit from a good engagement rate.
One of the goals of an influencer marketing campaign is to build a relationship of trust with someone who has an audience that interests you. Make sure you choose someone whose work you enjoy and whose style of content matches your image. Some companies choose to collaborate with influencers as brand ambassadors, which means an exclusive contract over a longer period.
The important thing is to target your campaign objectives and understand the benefits of each influencer groups.