With Channel Help, it is possible to add buttons under messages.
You can’t add buttons to Albums (multiple photos/videos together) due to Telegram limitations.

A button that when pressed redirects you to the inserted link.
To create it, you need to send the bot a phrase structured like this:
button text - button link
Replace "button text" with the text you want the button to have and "button link" with the actual link.
Example:

A button that, when pressed, shows a specific message via a pop-up.
There are two types of popup buttons:
Popup
Alert
The first is a full-screen pop-up that requires confirmation to close:
The second one is less intrusive and automatically closes after a few seconds.
To create it, you need to send the bot a phrase structured like this:
button text - popup:Popup text or button text - alert:Alert text
Replace "button text" with the text you want the button to have, and "Popup text" with the message for the pop-up.
Example:
If you want to wrap the popup message, enter \n as the line separator.
Example: Press here - popup: First line\nSecond line\nThird line
With the Popup button, you can show different text for users who are subscribed and those who are not subscribed to your channel.
To do this, send the bot a phrase structured like this:
button text - popup:Text for subscribed users %% Text for non-subscribed users
A button that, when pressed, copies the specified message to the user's clipboard.
button text - copy: text to copy
Button that if pressed will refer to the comments section related to that post.
The comments button is used to make channel subscribers able to comment on a post that includes buttons.
Let's see how to proceed to enable this button:
First of all a "discussion" group must be created and added from the channel settings.

The Channel Help bot must also be added to the discussion group.
Click here to add it.
Now that the button has been enabled, to create it you need to send the bot a sentence structured like this:
button text - comments
Replace "button text" with the text you want the button to have. Instead, you don't have to replace the comment keyword.
Example:

A button that allows you to share a text with someone once pressed.
Each user who presses the button will be able to choose a chat and the text to be shared will be automatically inserted in the message box of that chat.
To create it, you need to send the bot a phrase structured like this:
button text - share:Text to share
Replace "button text" with the text you want the button to have and "Text to share" with the text you want users to share.
Example:

It is possible to create buttons with the background in one of the following colors
Green - #g
Red - #r
Primary - #p
To color a button, you need to add the specific hashtag at the beginning of the button text:
#g Green button - linkbutton.com
#r Red button - linkbutton.com
#p Primary button - linkbutton.com
If you do not send any hashtag, the button will be colored with the standard button color.
It is possible to create buttons with a premium emoji at the beginning of the text.
To do this, simply insert a premium emoji in the button text:
ATTENTION: it is possible to set only a single premium emoji in each button.
You can create multiple buttons, of any type, to be added all together at the end of a post.
To create several buttons on the same line (for example buttons with links), the && character must be sent as separator:
text1 - link1 && text2 - link2 && text3 - link3
Example:

To create several buttons on several rows, you need to start a new line to separate one row from another.
text1 - link1 && text2 - link2
text3 - link3 && text4 - link4
Example:
