For the ease of your travel to Ukraine, it is best if you could read the tips in this page. Visa is required in most countries when you will travel aside from your visa. Now in the country of Ukraine, there are exceptions to the requirement of the visa. The citizens that come from the European Union, Canada, country of Japan, the United States, the Swiss Confederation, and Liechtenstein do not need to have their visas anymore to be able to travel to Ukraine.
The only requirement is that they will stay in Ukraine for a short time (90 days). After 90 days, they should have a visa. Check for updates as there may be changes from this law.
If you are at the entrance of Ukraine, you will have two choices of entry. Through the red or the green corridors of custom. Do not forget to keep all the documents that you are given and the ones you have filled out. You will have to present them when you will leave the country.
The red corridor is where the ones who have cash or goods they are carrying that are needed to be declared. Example of the things that should be declared when you will get to Ukraine is the pieces of jewelry that its value exceeds $240. The tobacco products that exceeded the 200 grams limit should also be declared. There is also the limit of cash you should declare. If you have nothing to declare then you just go to the green corridor.