This will vary according to the size of your website and how authoritative it is in Google’s eyes. A well-established site with millions of users and rapidly changing content, like the BBC home page for example, will get crawled extremely frequently (multiple times per hour) but a newly indexed websites with a few static pages and no links may only get crawled every few days.
To see how often you are getting crawled you can see a chart in your Google Search Console account.
To see which search engine bots are crawling your site the best place to start is to check your server logs. Server logs can be difficult to get at, depending on your technology stack and technical skills and can be very large. We have a new product in beta that makes this much, much easier – feel free to contact us for a free trial.