Sometimes, you want to share only part of a base while keeping other parts hidden. In these cases, it doesn't make sense to add the person with whom you're sharing with as a collaborator, because a collaborator can always see every part of the bases they are collaborating on.
Sharing part of a base for someone to read
Creating a synced table
Sharing part of a base for someone to edit
Creating a share link and a form
Creating a separate base
Sharing part of a base for someone to read
When sharing part of a base for someone to read, you can create a read-only view share link. Anyone with the view share link can see the contents visible in the specified view, and importantly, they will not see any records (rows) or fields (columns) that are hidden in this view.
Please be aware that the viewer of a table view share link will always see the most up-to-date version of the view. This means that if (for example) you change cell values, add records or fields, or toggle which fields and records are visible in a view, those changes will be reflected in the view share link.

If you would like to share more than one table from a base without showing the entire base, then you will need to create separate share links to each table. You can share an entire base (with nothing hidden) by creating a base share link.

An alternative to creating share links is emailing records.
Creating a synced table
Airtable Sync allows you to share a view from a source table with a targeted destination table in another base. The records synced with this targeted table cannot be updated, but they can be enriched by adding new fields. A basic overview can be found at the link above.
Sharing part of a base for someone to edit
Someone can directly edit records in a base only by being a collaborator on a base, and by therefore having access to the entire base. Therefore, if you would like someone to make changes to the base without having access to the entire base, you should not make that person a collaborator on that base. Instead, you can use one of the following techniques:
Creating a share link and a form
One common workaround is to create a view share link (explained above) and a form. With the share link, you can show someone just the specific records/fields from a table that you want them to see. Other people can then add records to the base through the form.
Please note that forms can only be used for adding new records, and not for editing existing ones.

As an alternative to creating a share link, you can also email records.
Creating a separate base
If you need someone to have the ability to fully edit and add records to just part of a base, you can add them as a collaborator to a separate base, into which you have copied and pasted just the records/fields you would like them to see.