When you work with any Component or Collection layout, you're usually displaying values from a column in your table. These are therefore referred to as Column Values.
For example, in this app, each item's title is displayed from the Column Values under the "Item" column found in the data source. It is also displaying the Column Values under the "Picture" column for each item's picture, and the Column Value under "Collection" as the header.
In the app below, the title component is displaying a mixture of Column Values and Custom Values.
The title is displaying the Item column value
The details is displaying the custom value of Item Details
The image is displaying the column value Picture
Column Values in Submission Screens
Column values are also used in submission screens. They can be used to send values from the current item to a table that stores submissions.
When you submit a Form, you ask users to fill in certain data that gets sent to your sheet or table. Sometimes those forms are submitted from collection items that contain relevant data. This is where column values are useful.
For example, the app below is an app for a store. Users can submit a form to ask questions about the item they are looking at.
When they tap Ask a question a form is triggered and the submissions go to your submissions table.
You could create multiple Text fields in the form that ask the user to input which item they're referring to, but that isn't a great user experience.
Instead, you can pass column values directly from the collection item into the form so that, when a form is submitted, the item's name, price and any other details you choose get submitted with the form.
Here we can see that your column values are Product, Description, Price, and Picture 1, because those are the columns in the sheet that contains your Form button.
Add these columns to your form when customizing it and match them with an empty column in your submissions sheet. Then, when your form is submitted, these column values will be passed along with the submission so it's clear which item the form was submitted in.