The Rich Publisher Apps platform gives you all the necessary tools for creating and integrating interactive apps into your feed’s publisher.

There are three ways to add a Rich Publisher App to your community.

1. Get it from AppExchange.

2. Build a custom app in your org.

3. Port an app through change sets or packages.

Creating Rich Publisher App:

1. Create the below Lightning Components.

Composer Component:

<aura:component implements="lightning:availableForChatterExtensionComposer">
    
    <aura:attribute name="options" type="List" default="[
    {'label': 'Thank You', 'value': 'Thank You'},
    {'label': 'Amazing Work', 'value': 'Amazing Work'}
    ]"/>
    <aura:attribute name="selectedVal" type="String"/>
    
    <lightning:radioGroup label="Radio Button Group"
                          options="{! v.options }"
                          value="{! v.selectedVal }"
                          onchange="{!c.appreciate}"/>
    
</aura:component>

Composer Component Controller:

({
    
appreciate: function(cmp, event, helper) {
        var compEvent = cmp.getEvent("sendChatterExtensionPayload");
        var selectedValObj = {value : cmp.get("v.selectedVal")};
        compEvent.setParams({
            "payload" : selectedValObj,
            "extensionTitle" : "Apprecication",
            "extensionDescription" : "Appreciation"
        });
        compEvent.fire(); 
    }
    
})

Renderer Component:

<aura:component implements="lightning:availableForChatterExtensionRenderer">
    
    {!v.payload.value}
    
</aura:component>

2. Go to Chatter Tab.Upload an icon to refer. In my example I have used Appreciation icon.

3. Get the File Id.

4. Go to https://workbench.developerforce.com/login.php and log in.

5. Go to Utilities –> REST Explorer.

6. Do a POST request with the below URL and body as {}.

/services/data/v43.0/connect/files/069f40000017eed/asset

069f40000017eed is the file id from step 3.

7. Get the fileAsset id.

8. Go to Data –> Insert.

9. Select ChatterExtension. Select Single Record. Click Next button.

10. Enter the values as below and click Confirm Insert.

Adding Rich Publisher App to Community:

1. Go to All Communities.

2. Select the Community for which you want Rich Publisher Apps.

3. Select Administration.

4. Click Rich Publisher Apps.

5. Select the apps and save.

Output: