Step 1: In ArcGIS Pro 2.6, open a project in the Catalog view and double-click on the Styles folder. How to Create Your Own Style in ArcGIS Pro

Follow the steps below to learn how to create a web style and use it in Map Viewer beta. The Esri symbols provide a glimpse into the power of leveraging multiple layers in a symbol. The current symbol styler offers limited control on these layers, but there will be full support in a future update. These new styles give you more control when customizing symbols by allowing you to use one or more symbol layers to create the desired effect. You can use the new styles to display multilayer vector symbols for features. The web style can be used in multiple maps by organization members. You can share the web style with a selected group in your organization.

You can use the symbols to author web maps in Map Viewer and ArcGIS API 4 for JavaScript, as well as newer versions, and applications such as ArcGIS Experience Builder and ArcGIS Dashboards beta.

These symbol galleries are published as web styles and can be a collection of picture and shape marker symbols for styling point features. With the release of ArcGIS Pro 2.6 and Map Viewer Beta, you can now publish your own 2D symbols to ArcGIS Online.

Creating symbols in illustrator