Filter needs a Pro widget. The hashtag options need the Pro or Developer plan. Every paid plan starts with a 14-day free trial. See the pricing page.
Set a filter
1
Open your widget
On your dashboard, click the widget.
2
Choose a filter
On the Basic tab, select an option in Filter. For a hashtag option, type the hashtag in Hashtag without the 
# sign.
3
Save
The preview shows the posts. Then click Install Widget to save. You do not need to change the code on your website.
Instagram filters
The Instagram Feed layout has no Filter setting.
X (Twitter) filters
See X hashtag widget for the full steps.