Dimension Style Manager
Accessing the Dimension Style Manager: To view the Dimension Style Manager dialog box, click the Dimension Style button from the Ribbon Annotate tab - Dimensions panel. Alternatively, you can type "DDIM" in the command line and press Enter.
Creating a New Dimension Style: In the Dimension Style Manager dialog box, you can create a new dimension style by clicking the New button. Give your style a name, and then adjust the settings as needed.
Modifying an Existing Dimension Style: Select an existing style from the list, and then click the Modify button. Make your changes, and then click OK to save them.
Properties
Dimension Properties: To adjust the properties of an individual dimension, select the dimension and then use the Properties palette. Here, you can change settings such as the dimension style, text size, and more.
Dimension Associativity: By default, dimensions are created as associative, meaning they will automatically adjust if the geometry then dimension is modified. This feature can be controlled from the AutoCAD Options dialog box, where you can tick or untick the Make new dimensions associative option