You can change zoom levels for:
Column Size
Card Detail
Font Size
To change the zoom level, follow through these steps:
Click on the Eye Icon next to the Board View option.
A drop down will appear
Hover to the Zoom option at the end of the drop down.
Once you hover on to the Zoom Menu, you will have the following options
Column Size
Using the slider, you will be able to increase the size of the sprint columns on the board.
Card Detail
This option will reduce the amount of content on the Feature Card.
Selecting the ID option will show only the ID and the Dependency Counter of the Feature while the Title, Status, Number of User Story Points, and Number of User Stories will not be visible.
Selecting the ID+Title option will show only the ID, Title and the Dependency Counter of the Feature while the Status, Number of User Story Points, and Number of User Stories will not be visible.
Selecting the Full option will show the ID, Title, Dependency Counter, Status, Number of User Story Points and Number of User Stories of the Feature.
Font Size
Using this slider will only alter the size of the Feature, User Story title and the Iteration(Sprint) labels and dates.
Clicking on the Reset button, will revert all of your changes back to the original zoom levels.