Update README.md

README.md

@@ -1 +1,35 @@
-# Document
+# Brazilian Document Validation
+
+This Go package provides functions to validate Brazilian CPF and CNPJ numbers. CPF (Cadastro de Pessoas Físicas) is a unique identification number given to Brazilian citizens, while CNPJ (Cadastro Nacional da Pessoa Jurídica) is a unique identification number given to Brazilian companies.
+
+## Installation
+To use this package, you need to have Go installed on your computer. Then, open a terminal and run the following command:
+```go
+go get github.com/DanielFillol/Document
+```
+
+## Usage
+Import the package into your code:
+```go
+import "github.com/DanielFillol/Document"
+```
+
+### ValidateCPF
+The ValidateCPF function takes a string as input and returns a boolean value indicating whether the input is a valid CPF number. If the input is not a valid CPF number, the function returns false.
+```go
+isValid := document.ValidateCPF("123.456.789-09")
+```
+
+### ValidateCNPJ
+The ValidateCNPJ function takes a string as input and returns a boolean value indicating whether the input is a valid CNPJ number. If the input is not a valid CNPJ number, the function returns false.
+```go
+document.ValidateCNPJ("12.345.678/0001-00")
+```
+
+## How it works
+The validation process for both CPF and CNPJ numbers is based on a set of rules defined by the Brazilian government. The rules include checks for the number of digits, the format of the number, and the validity of the verification digits.
+
+The verification digits are calculated using a weighted sum of the digits in the number, where each digit is multiplied by a specific weight. The resulting sum is then divided by a specific value, and the remainder is used to calculate the verification digit.
+
+## Contributing
+If you find a bug or have a suggestion for improvement, please open an issue or submit a pull request on GitHub. We welcome contributions from the community.