There are services that allow you to do this. Attempting to do this on your own, without any experience you're going to run into alot of issues. you're about 2 years too late. If you have the time, and money to go thru the learning and testing process then yeah, it's possible to do on your own.... just need to find someone to explain it step by step.
The problems that you will run into nowadays with bulk DMs is the sending limit is different on every account session, if you're sending to your followers you're limited to 35-50 DMs a day. If you choose to send to non followers, the number increases to 100+ but you can expect that all the messages will goto the spam box as they're not following you. You're going to need to purchase proxies for the accounts. You're going to need to create/buy "scraper" accounts... to scape the users you want to send the DMs to, as you're no longer able to scrape directly without being logged into an account, and even when you're logged in you're limited on the amount of api calls you can make. Those are just a few of the issues you can expect to face if you're intending on sending bulk DMs on IG.
If you're a white label, and you're just looking to promote your brand/product/website.. then i would just go with one of the DM services out there. They're able to send 100k DMs for a fraction of the price of what you would if you ran the setup on your own. Good luck.
