You can change or remove arrows on the borders of charts with the Shape Outline tool on the Format tab in PowerPoint. Microsoft Office does't allow arrows as the actual borders of a chart or shape ...

While there isn't a built-in option for adding borders to a slide in PowerPoint, there is a workaround. You can add a border to a PowerPoint slide by adding a rectangle shape and removing the fill ...

Follow the steps below to add and remove Borders or Outlines from Text Boxes or around Paragraphs in Microsoft PowerPoint. Launch Microsoft PowerPoint. Then insert a text box into your slide.