TLDs are Top-Level Domains which are commonly used in the internet domain name system, .COM (Commercial) or .ORG (Organization) are the more commonly known ones. However, most of these names have been extensively registered and hence, there are limited availability of such names for new registrations.
ccTLDs stands for Country-Code Top Level Domains and are country-specific. Using a country-specific TLD gives a clear understanding of the country where the business or person is located. For example in Singapore, it would be companyname.sg or companyname.com.sg.
A ccTLD allows for better internet traffic direction where users will know that you are based locally in the country, thus increasing the chances of your website being visited by potential customers in the country. Some ccTLDs such as .SG allow names in languages like Chinese, Tamil or even Cyrillic.