Click on the Text Element button on top header bar.

A text element will appear on the canvas.

Name: You can edit the name of the image to easily distinguish it from other elements you put on the canvas. 

Value:  As mentioned above, this field is where you enter and edit your text. Also, when you pick a datasource field for your dynamic texts, you can see the datasource path here. 

Refresh icon: In case you add the text via a datasource, this icon updates text area, and the current text in the datasource is reflected on the canvas. 

Delete and duplicate icons are self explanatory.

Font-family: Select among many options. 

Font-size: Select the size of your text.  It is 120 px by default. 

Bold & Italic icons are self-explanatory. 

Text Color: Select the color by the dropper or entering a hex value. 

Alignment icons are for you to select where the text will appear in the text box. The icons are for the text to be left aligned, centered and right aligned, respectively.

Box settings are opacity, radius and fill. Fill is the background color of the text container. Fill does not have a default value (it is transparent). You can select a fill color when you need a background for your text. 

You can check the transform and arrangement settings from here.

Click on the Shape Element button on top header bar.

This will open a modal box that includes shapes. Choose one you like.

Your shape will appear on the canvas. Shapes do not have a name or value.

You can change the color, delete or duplicate a shape.

Box, Transform and Arrangement functions are stand-alone topics.