Since there is no eve-api for signatures they can only be pasted to browser versions of eveeye. On mobile apps however you can see signatures shared by pilots within your group.
You can copy and paste signatures from the EVE client using
Ctrl+C an paste them on the active browser window of Eveeye.
ADD signatures to the system.
OVERWRITE all sigs within that system with the pasted ones.
Shift+Ctrl+V does not work in Firefox browser.
Signatures get pasted to your current ingame location. If you are not syncing your location sigs get added to the system you are showing info on.
Pasting sigs will open the SIG info tab of solarsystem info pane. In that tab signatures and wormhole connection data get shown. In browser version you can drag wormhole signatures onto wormhole connections to merge the signature ID.
Using the filter buttons you can toggle the display of those signatures or connections.
A signature can be deleted by clicking the
X top right of it and confirm.
Deleted sigs can be undeleted for up to 3 hours. You can show and hide anomalies, cosmics and deleted sigs by clicking the corresponding tab above the signatures displayed.
The length of the bars to the left and right of the system node reflect the sig count of the corresponding type.
If you turned on Data Sharing your signatures will get displayed to all other pilots in your sharing group.