Select the folder and click File → Compress from the top menu. Alternatively, select the folder with control-click, right-click, or a two-finger touchpad click. This opens a drop-down menu that includes Compress. Use the attach function as you would for any file, then select the compressed folder. Some users report a bug in the Mail app that selects the folder that contains the one you select. If this happens, switch the folder to "list view" and try again. If the compressed folder is still too large for your email client, you can try one of these workarounds:  If you're using iCloud Mail, click the gear icon in the sidebar, then Preferences. Under Composing, select "Use Mail Drop when sending large attachments." Now you can attach files up to 5 GB, although the download link will only remain for 30 days.  Separate the contents of the folder and send the files in several emails.  Upload the files to a free cloud storage service.

TL;DR in Indonesian:
Kompresi berkas yang ingin Anda kirim dengan memilih berkas dan mengeklik File > Compress dari menu di bagian atas layar. Pilih folder terkompresi, lalu lampirkan folder pada surel Anda layaknya berkas biasa. Atasi masalah saat pengiriman surel.