Le billet électronique est sur mon téléphone.

Le is the masculine singular definite article, meaning the.

In French, you usually need an article before a noun, much more often than in English. So French says le billet électronique where English might say the e-ticket or sometimes just e-ticket in a short message.

Here, le suggests a specific ticket: the one already known in context.

In French, most adjectives come after the noun they describe.

So:

• un billet électronique = an electronic ticket
• un téléphone portable = a mobile phone

English often puts adjectives before the noun, but French usually puts them after. That is why électronique follows billet.

The adjective must agree with the noun it describes.

Here:

• billet is masculine singular
• so the adjective is also masculine singular: électronique

This adjective has the same form in the masculine and feminine singular:

• un billet électronique
• une version électronique

But the plural adds -s:

• des billets électroniques

Because téléphone is a masculine noun.

French possessive adjectives agree with the noun possessed, not with the owner.

So:

• mon téléphone = my phone
• ma voiture = my car
• mes clés = my keys

It does not matter whether the speaker is male or female. A woman would also say mon téléphone.

French often uses sur (on) for digital content that is stored, shown, or accessible on a device.

So:

• sur mon téléphone = on my phone
• sur mon ordinateur = on my computer

This matches English quite closely, since English also often says on my phone.

You might sometimes hear dans mon téléphone, but that usually sounds less natural here. Sur mon téléphone is the standard choice for something available on the device.

Yes, it is natural and clear.

It means that the electronic ticket is available or stored on the speaker’s phone. In everyday French, people might also say:

• J’ai mon billet sur mon téléphone.
• Mon billet est sur mon téléphone.
• J’ai le billet électronique sur mon téléphone.

All of these are natural, but your sentence is perfectly correct.

Yes. E-billet is also common, especially in travel contexts.

For example:

• L’e-billet est sur mon téléphone.

Both billet électronique and e-billet are used.
Billet électronique sounds a bit more fully French and slightly more formal, while e-billet is common in modern usage.

Est is the third-person singular form of être (to be).

The subject is Le billet électronique, which is singular, so French uses:

• il est / le billet est = it is / the ticket is

So:

• Le billet électronique est sur mon téléphone. literally follows the pattern:
• The electronic ticket is on my phone.

A careful pronunciation is approximately:

luh bee-yay ay-lek-troh-neek eh sur mon tay-lay-fohn

A few important points:

• billet sounds like bee-yay
• électronique has stress spread fairly evenly, unlike English
• téléphone sounds roughly like tay-lay-fohn
• the final -t in est is normally not pronounced here

In natural speech, le billet électronique may flow together smoothly, but there is no strong required liaison after est before sur.

Both can refer to a phone, but they are used a bit differently.

• téléphone = phone
• téléphone portable = mobile phone / cell phone
• portable on its own often means mobile phone in everyday French, especially in France

So you could also hear:

• Le billet électronique est sur mon portable.

That is very natural in everyday speech.
Your sentence with mon téléphone is also completely correct and easy for learners.

Not necessarily.

Le billet électronique est sur mon téléphone usually means the ticket is on the phone in a general sense:

• stored there
• accessible there
• saved there
• available to show

It does not have to mean that it is currently visible on the screen at this exact moment. If you wanted to make that idea clearer, you might say something like:

• Le billet est affiché sur mon téléphone. = The ticket is displayed on my phone.

Accent marks are a normal part of French spelling, not optional decoration.

Here they help show pronunciation:

• é is pronounced like a clear ay sound
• è would sound different
• the accents in téléphone help guide the correct vowel sounds

So you should write:

• électronique
• téléphone

and not leave the accents out in normal French writing.