When you are filtering in the Explore section, you can type filter values into a filter box with commas as separators. Looker will automatically parse out the commas, and each filter value will show up as a separate box. If you have filter values with commas in them that you not like parsed out, check out this article.
You may have many filter values, such as a list of IDs, that you want to paste in to a Looker filter. The best way to do this is to paste in a comma-separated list. For example, if I have this list of values:
Accessories, Blazers & Jackets, Fashion Hoodies & Sweatshirts, Pants, Shorts, Sweaters
I can paste it into a filter, and they will be parsed into separate filter values:
If this doesn't work, you can also paste this comma-separated list into a filter of type matches (advanced). This would look something like: