After you have created a Shipment record you can view the Shipment record in Salesforce. The label will be attached as a related attachment to the Shipment record in its raw form as received from the shipping carrier.
Click on the Print Label button or link on the field on the layout. Clicking this button will orient the image of the label vertically, and will display the image in the width and height that is set in the fields Label Width and Label Height. You may not need to adjust these fields depending on the outcome of the print and considering the following steps. If you do need to adjust the width and heigh you can set these fields values. The width and height is in pixels so you can start with 400 for width and 600 for height and then adjust from there to get it how you need for your printer and paper. If you determine you need to set the Label Width and Height on the Shipment record then you should configure a Salesforce Workflow or Process Builder to set the values of those two fields with the values you need when a new Shipment record is created. This way it is already set for every record and ready to print.
When you click the Print Label button it also should prompt the Print action on the browser. When you print from your browser, your browser will have some printing options such as to Adjust the image to fit to a whole page or to scale an image. You can select paper size and there are also settings with your printer and paper setup to configure margins and width and height. There are many browsers, printers, paper, labels and options here. You will need to adjust your settings between the printer, paper, browser, and potentially the label width/height on the Shipment record to find the right conditions to print the label the way you need.
Optionally you can also view the label attachment directly from the Attachments related list and consider printing from that direct image.
If you are mass printing labels we suggest you utilize the Google Drive feature of the shipment app which you can configure in Ship Configuration tab. All shipping labels will be saved to your google drive to a folder you select. You can create a folder on your google drive called “Ship Labels to Print” that is a holding folder for labels to print. A person would then go to the google drive folder and do an export of all the label files into a zip file. Then open that zip file on the computer after downloaded and unzip. Then you will have a folder of a bunch of labels to print in mass using mass print function on the computer. You may also consider syncing the google drive folder with your desktop to skip zip file export step. Then we suggest having another google drive folder called “Ship Labels Printed” so that once you export/download/print the labels in the “Ship Labels to Print” folder you can select all those files and move them to the other folder to keep the label file but move it out of this “processing” folder so that it is empty and ready to be filled by new shipment labels that need to be printed.