For every overlay you are adding you can add effects
To enable overlay select, Show Overlay
Go to Style - Overlay - Background Type, Select classic and then choose the image or gradient you have to show in overlay
You can also edit the color if you have selected gradient or edit the image size, position, attachment and repeat.
Then comeback again to the content tab and under overlay you can edit the Hover Effects.
you can also control the transition duration of the overlay effects
Under Style,
You can edit the Border effect. under Border,
Solid - A solid border line is applied to the overlay
Double - A double border line is applied to the overlay
Dotted - A border with dotted lines is applied to the overlay
Dashed - Border is applied with dashed lines to the overlay
Grooved - Border like which is grooved to the overlay is applied
You can also edit the width, color and margin of the border in the elementor
Under Background type you can add classic or gradient for an overlay
If you have selected Gradient,
you will be getting the options to select the color for the gradient, you can select up-to two colors for the gradient effect
you can also select the location of the colors, i.e., the height for the displayed colors in an overlay
you can also select the type of the gradient effect either radial or linear, radial gives circular gradient effect and the linear gives horizontal gradient effect
For Linear effect you can select the angle from 0° to 360° degree
For Radial effect you can select from the list of effects under position
If you have selected Classic,
you can add background image as an overlay
you can adjust the position, attachment, repeat and size of the image based on your requirement