SevenZipArchive.CreateEntry

public SevenZipArchiveEntry CreateEntry(string name, FileInfo fileInfo, 
    bool openImmediately = false, SevenZipEntrySettings newEntrySettings = null)

using (FileStream sevenZipFile = File.Open("archive.7z", FileMode.Create))
{
    FileInfo fi1 = new FileInfo("data1.bin");
    FileInfo fi2 = new FileInfo("data2.bin");
    FileInfo fi3 = new FileInfo("data3.bin");
    using (var archive = new SevenZipArchive())
    {
        archive.CreateEntry("entry1.bin", fi1, false, new SevenZipEntrySettings(new SevenZipStoreCompressionSettings(), new SevenZipAESEncryptionSettings("test1")));
        archive.CreateEntry("entry2.bin", fi2, false, new SevenZipEntrySettings(new SevenZipStoreCompressionSettings(), new SevenZipAESEncryptionSettings("test2")));
        archive.CreateEntry("entry3.bin", fi3, false, new SevenZipEntrySettings(new SevenZipStoreCompressionSettings(), new SevenZipAESEncryptionSettings("test3")));
        archive.Save(sevenZipFile);
    }
}

public SevenZipArchiveEntry CreateEntry(string name, Stream source, 
    SevenZipEntrySettings newEntrySettings, FileSystemInfo fileInfo)

using (FileStream sevenZipFile = File.Open("archive.7z", FileMode.Create))
{
    using (var archive = new SevenZipArchive())
    {
        archive.CreateEntry("entry1.bin", new MemoryStream(new byte[] {0x00, 0xFF}), new SevenZipEntrySettings(new SevenZipLZMA2CompressionSettings(), new SevenZipAESEncryptionSettings("test1")), new FileInfo("data1.bin")); 
        archive.Save(sevenZipFile);
    }
}

public SevenZipArchiveEntry CreateEntry(string name, Stream source, 
    SevenZipEntrySettings newEntrySettings = null)

using (var archive = new SevenZipArchive(new SevenZipEntrySettings(new SevenZipLZMA2CompressionSettings(), new SevenZipAESEncryptionSettings("p@s$"))))
{
    archive.CreateEntry("data.bin", new MemoryStream(new byte[] {0x00, 0xFF} ));
    archive.Save("archive.7z");
}

public SevenZipArchiveEntry CreateEntry(string name, string path, bool openImmediately = false, 
    SevenZipEntrySettings newEntrySettings = null)

using (FileStream sevenZipFile = File.Open("archive.7z", FileMode.Create))
{
    using (var archive = new SevenZipArchive(new SevenZipEntrySettings(new SevenZipLZMA2CompressionSettings())))
    {
        archive.CreateEntry("data.bin", "file.dat");
        archive.Save(sevenZipFile);
    }
}