Tafadhali andika namba yako ya simu kwenye fomu.

Tafadhali means please. It makes the instruction more polite.

In this sentence, it comes at the beginning:

Tafadhali andika namba yako ya simu kwenye fomu.

But it can also appear at the end:

Andika namba yako ya simu kwenye fomu, tafadhali.

Both are natural.

In Swahili, commands usually do not need an explicit subject, just like in English Write your phone number.

So andika here is the singular imperative, meaning write! and addressed to one person.

You do not normally say wewe andika unless you want special emphasis, contrast, or correction.

Andika is the imperative form of the verb -andika, meaning to write.

So:

• -andika = to write
• andika! = write! (to one person)

If you were speaking to more than one person, you would usually say:

• andikeni = write! (to several people)

Swahili often builds noun phrases in a way that is more literally like:

number your of phone

That sounds strange in English, but it is normal in Swahili.

Here is the structure:

• namba = number
• yako = your
• ya simu = of phone

So namba yako ya simu means your phone number.

A useful way to think of it is:

• first the main noun: namba
• then possession: yako
• then a further description: ya simu

Yako means your, but specifically it agrees with the noun namba.

It is made from:

• ya- = the agreement part for this noun class
• -ko = your

So:

• yangu = my
• yako = your
• yake = his/her
• yetu = our
• yenu = your (plural)
• yao = their

Because namba belongs to a noun class that uses ya- for this kind of agreement, you get yako here.

That ya is a linking word often translated as of.

So:

• namba ya simu = phone number
• literally: number of phone

This ya agrees with namba, the noun being described.

Swahili uses this kind of linker very often:

• kitabu cha mwanafunzi = the student’s book / book of the student
• mlango wa nyumba = the door of the house
• namba ya simu = phone number

Kwenye is a locative word meaning something like on, in, or at, depending on context.

In this sentence, kwenye fomu means on the form.

So:

• kwenye meza = on the table
• kwenye sanduku = in the box
• kwenye fomu = on the form

English chooses different prepositions here, but Swahili often uses kwenye more broadly.

Yes, you may hear katika fomu, but kwenye fomu is very natural for on the form.

A rough difference is:

• kwenye often feels like on / in / at a place or surface
• katika often feels more specifically inside / within

Because a form is something you write on, kwenye fomu is especially appropriate.

Fomu is a loanword, from English form.

Swahili uses many loanwords, especially for modern or administrative vocabulary.

Like many loanwords, fomu commonly stays the same in singular and plural, with meaning understood from context.

Swahili does not have articles like English a and the.

So a noun like fomu can mean:

• a form
• the form

The exact meaning depends on context.

That is why kwenye fomu can naturally mean on the form even though there is no separate word for the.

The basic order here is very natural:

• Tafadhali = please
• andika = write
• namba yako ya simu = your phone number
• kwenye fomu = on the form

So the pattern is:

please + verb + object + location

This is the most straightforward order for this sentence.

You can move tafadhali:

• Tafadhali andika namba yako ya simu kwenye fomu.
• Andika namba yako ya simu kwenye fomu, tafadhali.

But the rest of the sentence is best kept as shown for a learner.

No. You may also see nambari.

Both namba and nambari are used, and both can mean number.

For everyday speech, namba ya simu is very common and natural for phone number.

You would normally change the command form of the verb:

• Andika = write! (to one person)
• Andikeni = write! (to several people)

So the plural version would be:

Tafadhali andikeni namba zenu za simu kwenye fomu.

Notice that other words also change:

• yako = your (singular)
• zenu = your (plural)
• ya simu becomes za simu because namba is now plural in meaning and the agreement changes accordingly.