Now when you log into your Google My Business account on the left hand side you can see they have added the ability to add posts. The posts can be from 100-300 characters, add an image and add an event and or button to whatever it is you are talking about.
Here is an example of one I set up today:
You can’t embed the post yet and I hope that is something they will add so I had to link to the post. But here is an embed of me sharing the same post on Twitter:
— Ysais SEO (@Ysais_AustinSeo) June 23, 2017
The hashtag is set up to tag Google automatically and there is a pre-made message but I would suggest adding a few of your own hashtags and adding your own keywords if you would like.