要保存申请表的号码，以便查询进度。
Keep the number of the application form, in order to follow up the process.
“以便” yǐ biàn is a formal way to say “in order to ”. It is normally used to express a purpose or an outcome of a particular action. Here are two examples:
| Action | 以便 | Purpose/Outcome |
|---|---|---|
| 需要护照和一些现金， | 以便 | 存入你的账户。 |
| (You) need your passport and some cash | in order to | deposit in your account. |
| 要保存申请表的号码， | 以便 | 查询进度。 |
| Keep the number of the application form, | in order to | follow up the process. |